As interactive apparatuses become much more popular nowadays, eye tracking technologies have become one of the important parts in the technologies of contact or non-contact interaction. The main working principle of eye tracking technologies is to capture an eye image by an image capture device, and identify a gaze point in the eye image as the basic interaction input information.
However, when a known image capturing apparatus captures an eye image, a contrast of the eye image may be insufficient, or an eye identifying feature may be shielded if glare caused by an external light source projecting light onto an eye region is captured or a light-transmitting medium, such as eyeglasses, a goggle, a protective mask, cosmetic lenses, contact lenses, or the like is present between the image capturing apparatus and the eye. Also, the contrast of the eye image may be insufficient due to various iris colors among different races. Thus, the glare, the insufficient contrast of the eye image, or the shielding of the eye identifying feature may possibly lead the eye tracking apparatus to misjudge the gaze point of the eye image and thus generate erroneous interaction input information.